We present glacier thickness changes over the entire Pamir–Karakoram–Himalaya arc based on ICESat satellite altimetry data for 2003–2008. We highlight the importance of C-band penetration for studies based on the SRTM elevation model. This penetration seems to be of potentially larger magnitude and variability than previously assumed. The most negative rate of region-wide glacier elevation change Read More

This chapter summarizes the current state of remote sensing of glaciers in the India, Nepal, and Bhutan regions of the Himalaya, and focuses on new methods for assessing glacier change. Glaciers in these Himalaya regions exhibit complex patterns of changes due to the unique and variable climatic, topographic, and glaciological parameters present in this region. The theoretical understanding of glaciers in the Himalaya is limited by lack of sufficient observations due to terrain breadth and complexity, severe weather conditions, logistic difficulties, and geopolitics. Mapping and assessing these glaciers with satellite imagery is also challenging due to inherent sensor limitations and information extraction issues. Thus, we still lack a complete understanding of the magnitude of feedbacks, and in some places even their sign, between climate changes and glacier response in this region. In this chapter we present the current status of glaciers in various climatic regimes of the Himalaya, ranging from the monsoon-influenced regions of the central-eastern Himalaya (Nepal, Garhwal, Sikkim, and Bhutan) through the monsoon transition zone of Himachal Pradesh (India), to the dry areas of Ladakh (western Himalaya). The case studies presented here illustrate the use of remote sensing and elevation data coupled with glaciermapping techniques for glacier area and elevation change detection and ice flow modeling in the context of the HimalayaRead More

The recent evolution of Pamir-Karakoram-Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To estimate the region-wide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan (eastern Himalaya), we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008–2011) DEMs derived from SPOT5 stereo imagery. During the last decade, the region-wide glacier mass balances were contrasted with moderate mass losses in the eastern and central Himalaya (−0.22 ± 0.12 m w.e. yr−1 to −0.33 ± 0.14 m w.e. yr−1) and larger losses in the western Himalaya (−0.45 ± 0.13 m w.e. yr−1). Recently reported slight mass gain or balanced mass budget of glaciers in the central Karakoram is confirmed for a larger area (+0.10 ± 0.16 m w.e. yr−1) and also observed for glaciers in the western Pamir (+0.14 ± 0.13 m w.e. yr−1). Thus, the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers, −0.14 ± 0.08 m w.e. yr−1, is two to three times less negative than the global average for glaciers distinct from the Greenland and Antarctic ice sheets. Together with recent studies using ICESat and GRACE data, DEM differencing confirms a contrasted pattern of glacier mass change in the PKH during the first decade of the 21st centuryRead More

Floods resulting from the outbursts of glacial lakes are among the most far-reaching disasters in high mountain regions. Glacial lakes are typically located in remote areas and space-borne remote sensing data are an important source of information about the occurrence and development of such lakes. Here we show that very high resolution satellite Synthetic Aperture Radar (SAR) data can be employed for reliably mapping glacial lakes. Results in the Alps, Pamir and Himalaya using TerraSAR-X and Radarsat-2 data are discussed in comparison to in-situ information, and high-resolution satellite optical and radar imagery. The performance of the satellite SAR data is best during the snow- and ice-free season. In the broader perspective of hazard management, the detection of glacial lakes and the monitoring of their changes from very high-resolution satellite SAR intensity images contributes to the initial assessment of hazards related to glacial lakes, but a more integrated, multi-level approach needs also to include other relevant information such as glacier outlines and outline changes or the identification of unstable slopes above the lake and the surrounding area, information types to which SAR analysis techniques can also contributeRead More

Himalayan glaciers are a focus of public and scientific debate. Prevailing uncertainties are of major concern because some projections of their future have serious implications for water resources. Most Himalayan glaciers are losing mass at rates similar to glaciers elsewhere, except for emerging indications of stability or mass gain in the Karakoram. A poor understanding of the processes affecting them, combined with the diversity of climatic conditions and the extremes of topographical relief within the region, makes projections speculative. Nevertheless, it is unlikely that dramatic changes in total runoff will occur soon, although continuing shrinkage outside the Karakoram will increase the seasonality of runoff, affect irrigation and hydropower, and alter hazardsRead More

A Landsat Thematic Mapper (TM) scene from 2003 covering the Jotunheimen and Breheimen region has been used to map the recent glacier extents using thresholded ratio images (TM3/TM5). Orthoprojected aerial photographs and glacier outlines from digital maps have been used to validate the method and control the results. The authors further calculated glacier changes by comparing the Landsat-derived 2003 glacier outlines with previous maps and inventories from the 1930s, 1960s and 1980s. Their results confirm that the applied automatic mapping method is robust and agrees with the reference data used. Some manual editing was necessary to correct the outline at ice-lake contacts and at debris covered glaciers. However, for most of the glaciers no corrections were required. The most laborious task has been to assign ID numbers and couple the new Landsat inventory to previous inventories to assess area changes. The glaciers investigated shrank since the 1930s with an overall area reduction of about 23% for 38 glaciers. Since the 1960s the area reduction was 12% for 164 glaciers. Although the general trend is glacier recession, some glaciers have increased their size or remained nearly unchanged over these decades.

Mountains and mountain societies provide a wide range of goods and services to humanity, but they are particularly sensitive to the effects of global environmental change. Thus, the definition of appropriate management regimes that maintain the multiple functions of mountain regions in a time of greatly changing climatic, economic, and societal drivers constitutes a significant challenge. Management decisions must be based on a sound understanding of the future dynamics of these systems. The present article reviews the elements required for an integrated effort to project the impacts of global change on mountain regions, and recommends tools that can be used at three scientific levels (essential, improved, and optimum). The proposed strategy is evaluated with respect to UNESCO's network of Mountain Biosphere Reserves (MBRs), with the intention of implementing it in other mountain regions as well. First, methods for generating scenarios of key drivers of global change are reviewed, including land use/land cover and climate change. This is followed by a brief review of the models available for projecting the impacts of these scenarios on (1) cryospheric systems, (2) ecosystem structure and diversity, and (3) ecosystem functions such as carbon and water relations. Finally, the cross-cutting role of remote sensing techniques is evaluated with respect to both monitoring and modeling efforts. The authors conclude that a broad range of techniques is available for both scenario generation and impact assessments, many of which can be implemented without much capacity building across many or even most MBRs. However, to foster implementation of the proposed strategy, further efforts are required to establish partnerships between scientists and resource managers in mountain areasRead More